Method and apparatus for processing buffer status report and communication system

ABSTRACT

A user equipment (UE), the UE including: a controller configured to control to trigger a Buffer Status Report (BSR) if an allocated uplink resource for a Transmission Time Interval (TTI) is capable of accommodating a Sidelink Buffer Status Report (BSR) Medium Access Control (MAC) Control Element (CE) containing a buffer status for at least one Sidelink Destination and its corresponding MAC subheader; and a transmitter configured to transmit the BSR, wherein, the controller controls to cancel all triggered Sidelink BSRs if no side-link data available for transmission exists.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/657,720, filed on Jul. 24, 2017, which is a continuation applicationof International Application PCT/CN2015/071548 filed on Jan. 26, 2015,the entire contents of each are incorporated herein by reference.

FIELD

This disclosure relates to the field of communication technologies, andin particular to a method and apparatus for processing a buffer statusreport and a communication system.

BACKGROUND

Currently, in a long-term evolution (LTE) system, communication betweenterminal devices needs to be performed via a radio access network and acore network. As appearance of demands for many new traffics, and at thesame time, in order to reduce a load of a network and achieve transferof the load of the network, the communication between terminal deviceshas gradually become a new direction for studies. When a distancebetween two terminal devices is sufficiently near, the terminal devicemay discover existence of the counterpart, hence, direct communicationbetween devices may be performed under control of an eNB.

In order to realize device to device communication, two types ofair-interface resource allocation schemes, mode 1 and mode 2, aredefined in an LTE-A (LTE-advanced) system. In mode 1, in order to avoidinfluencing reporting of a buffer status report (BSR) directed to atraffic of a conventional infrastructural communication mode, amechanism of BSR directed to the device to device communication (whichmay be referred to as a ProSe BSR) is introduced, which mainly includesa triggering mechanism of a new BSR and an MAC signaling format andcontent of the B S R.

Currently, two ProSe BSR formats are defined for device to device (D2D)communication, which are shown in FIGS. 1 and 2, respectively. The twoformats are both formats used for reporting ProSe BSRs in a case wherethere exist available to-be-transmitted data in ProSe destinations(sidelink destinations or sidelink targets). In other words, within aTTI transmitting ProSe BSRs, when all ProSe destinations have no data tobe transmitted, UE is unable to determine which formats should be usedby the reported ProSe BSRs.

A concept of a sidelink control period (briefly referred to as an SCperiod) is defined in the device to device (D2D) communication mode, theSC period referring to a time period containing scheduling control andtransmission of data to which it corresponds. For mode 1, a basicoperational principle of data transmission at a transmitter end in theD2D communication is as follows.

After scheduling of data transmission of a D2D user equipment (UE) isdetermined, an eNB transmits an SL grant (a sidelink grant) to the UEvia a physical downlink control channel (PDCCH) scrambled by a sidelinkradio network temporary identity (SL-RNTI), the SL grant containingtime-frequency resource positions of scheduling control (SC) to betransmitted by the UE and time-frequency resource positions of data tobe transmitted. A period of validity of the SL grant is one SC period,and an SC period to which it corresponds is a next SC period startingfrom 4 ms after a subframe transmitting the SL grant. After receiving anSL grant, the UE will first transmit the SC twice at a resource positionof the SC indicated by the SL grant within the SC period to which the SLgrant corresponds, and then transmit transport blocks (TBs) at resourcepositions of data indicated by the SL grant; wherein, each TB will betransmitted for four times, and the number of TBs that can betransmitted within one SC period is dependent on the number of resourcesallocated in the SL grant. FIG. 3 is a schematic diagram of thetransmission process.

It should be noted that the above description of the background ismerely provided for clear and complete explanation of this disclosureand for easy understanding by those skilled in the art. And it shouldnot be understood that the above technical solution is known to thoseskilled in the art as it is described in the background of thisdisclosure.

SUMMARY

In some cases, at a TTI moment when UE has sufficient uplink grants fortransmitting triggered ProSe BSRs, all ProSe destinations of the UE haveno available to-be-transmitted data. In such cases, at a TTI moment whenthe triggered ProSe BSRs may be transmitted, the UE is unable todetermine contents of a ProSe BSR MAC CE to be transmitted, hence, it isunable to report a current buffer status.

In order to solve the above problem, embodiments of this disclosureprovide a method and apparatus for processing a buffer status report anda communication system.

According to a first aspect of the embodiments of this disclosure, thereis provided a method for processing a buffer status report, applicableto user equipment (UE), the method including: whether in an TTI where anallocated uplink resource for the TTI is capable of accommodating aProSe BSR MAC CE containing a buffer status for at least one ProSeDestination and its corresponding MAC subheader is judged; if yes,whether there exist side-link data available for transmission in the TTIis judged; and if no, all triggered ProSe BSRs are cancelled.

According to a second aspect of the embodiments of this disclosure,there is provided a method for processing a buffer status report,applicable to user equipment (UE), the method including: whether in anTTI where an allocated uplink resource for the TTI is capable ofaccommodating a ProSe BSR MAC CE containing a buffer status for at leastone ProSe Destination and its corresponding MAC subheader is judged; ifyes, whether there exist side-link data available for transmission inthe TTI is judged; and if no, a ProSe BSR MAC CE with N being 1 and itscorresponding MAC subheader is reported, or a ProSe BSR MAC CE havingonly one buffer size domain and its corresponding MAC subheader isreported, or only one MAC subheader is reported.

According to a third aspect of the embodiments of this disclosure, thereis provided an apparatus for processing a buffer status report,applicable to user equipment (UE), the apparatus including: a firstjudging unit configured to judge whether in an TTI where an allocateduplink resource for the TTI is capable of accommodating a ProSe BSR MACCE containing a buffer status for at least one ProSe Destination and itscorresponding MAC subheader; a second judging unit configured to, whenit is judged yes by the first judging unit, judge whether there existside-link data available for transmission in the TTI; and a cancellingunit configured to, when it is judged no by the second judging unit,cancel all triggered ProSe BSRs.

According to a fourth aspect of the embodiments of this disclosure,there is provided an apparatus for processing a buffer status report,applicable to user equipment (UE), the apparatus including: a firstjudging unit configured to judge whether in an TTI where an allocateduplink resource for the TTI is capable of accommodating a ProSe BSR MACCE containing a buffer status for at least one ProSe Destination and itscorresponding MAC subheader; a second judging unit configured to, whenit is judged yes by the first judging unit, judge whether there existside-link data available for transmission in the TTI; and a reportingunit configured to, when it is judged no by the second judging unit,report a ProSe BSR MAC CE with N being 1 and its corresponding MACsubheader, or report a ProSe BSR MAC CE having only one buffer sizedomain and its corresponding MAC subheader, or report only one MACsubheader.

According to a fifth aspect of the embodiments of this disclosure, thereis provided user equipment, including the apparatus for processing abuffer status report as described in the third or the fourth aspect.

According to a sixth aspect of the embodiments of this disclosure, thereis provided a communication system, including user equipment; wherein,the user equipment is configured to: in an TTI where an allocated uplinkresource for the TTI is capable of accommodating a ProSe BSR MAC CEcontaining a buffer status for at least one ProSe Destination and itscorresponding MAC subheader, if there exist no side-link data availablefor transmission in the TTI, cancel all triggered ProSe BSRs, or reporta ProSe BSR MAC CE with N being 1 and its corresponding MAC subheader,or report a ProSe BSR MAC CE having only one buffer size domain and itscorresponding MAC subheader, or report only one MAC subheader.

According to another aspect of the embodiments of this disclosure, thereis provided a computer readable program code, which, when executed in anapparatus for processing a buffer status report or UE, will cause acomputer unit to carry out the method for processing a buffer statusreport as described in the first or the second aspect in the apparatusfor processing a buffer status report or the UE.

According to a further aspect of the embodiments of this disclosure,there is provided a computer readable medium, including a computerreadable program code, which will cause a computer unit to carry out themethod for processing a buffer status report as described in the firstor the second aspect in an apparatus for processing a buffer statusreport or UE.

An advantage of the embodiments of this disclosure exists in that withthe embodiments of this disclosure, a problem that UE is unable todetermine contents of a ProSe BSR MAC CE to be transmitted at a TTImoment when triggered ProSe BSRs can be transmitted is solved.

With reference to the following description and drawings, the particularembodiments of this disclosure are disclosed in detail, and theprinciple of this disclosure and the manners of use are indicated. Itshould be understood that the scope of the embodiments of thisdisclosure is not limited thereto. The embodiments of this disclosurecontain many alternations, modifications and equivalents within thespirits and scope of the terms of the appended claims.

Features that are described and/or illustrated with respect to oneembodiment may be used in the same way or in a similar way in one ormore other embodiments and/or in combination with or instead of thefeatures of the other embodiments.

It should be emphasized that the term“comprises/comprising/includes/including” when used in thisspecification is taken to specify the presence of stated features,integers, steps or components but does not preclude the presence oraddition of one or more other features, integers, steps, components orgroups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are included to provide further understanding of thisdisclosure, which constitute a part of the specification and illustratethe preferred embodiments of this disclosure, and are used for settingforth the principles of this disclosure together with the description.It is obvious that the accompanying drawings in the followingdescription are some embodiments of this disclosure, and for those ofordinary skills in the art, other accompanying drawings may be obtainedaccording to these accompanying drawings without making an inventiveeffort. In the drawings:

FIG. 1 is a schematic diagram of a format of a ProSe BSR MAC CE when Nis an even number;

FIG. 2 is a schematic diagram of a format of a ProSe BSR MAC CE when Nis an odd number;

FIG. 3 is a schematic diagram of a basic operational principle of datatransmission at a transmitter end in D2D communication;

FIGS. 4-8 are schematic diagrams of five application scenarios of anembodiment;

FIG. 9 is a flowchart of an implementation of a method for processing abuffer status report of Embodiment 1;

FIG. 10 is a flowchart of an implementation of a method for processing abuffer status report of Embodiment 2;

FIG. 11 is a flowchart of an implementation of a method for processing abuffer status report of Embodiment 3;

FIG. 12 is a schematic diagram of a format of an implementation of aProSe BSR MAC CE of Embodiment 3;

FIG. 13 is a schematic diagram of a format of an implementation of anMAC subheader of Embodiment 3;

FIG. 14 is a schematic diagram of a format of another implementation ofthe MAC subheader of Embodiment 3;

FIG. 15 is a schematic diagram of a format of another implementation ofthe ProSe BSR MAC CE of Embodiment 3;

FIG. 16 is a flowchart of an implementation of a method for processing abuffer status report of Embodiment 4;

FIG. 17 is a flowchart of an implementation of a method for processing abuffer status report of Embodiment 5;

FIG. 18 is a schematic diagram of a structure of an implementation of anapparatus for processing a buffer status report of Embodiment 6;

FIG. 19 is a schematic diagram of a structure of an implementation of anapparatus for processing a buffer status report of Embodiment 7;

FIG. 20 is a schematic diagram of a structure of an implementation of anapparatus for processing a buffer status report of Embodiment 8;

FIG. 21 is a schematic diagram of a structure of another implementationof the apparatus for processing a buffer status report of Embodiment 8;

FIG. 22 is a schematic diagram of a structure of the UE of anembodiment; and

FIG. 23 is a schematic diagram of a topology of the communication systemof an embodiment.

DETAILED DESCRIPTION

These and further aspects and features of the present disclosure will beapparent with reference to the following description and attacheddrawings. In the description and drawings, particular embodiments of thedisclosure have been disclosed in detail as being indicative of some ofthe ways in which the principles of the disclosure may be employed, butit is understood that the disclosure is not limited correspondingly inscope. Rather, the disclosure includes all changes, modifications andequivalents coming within the terms of the appended claims. Theembodiments of this disclosure shall be described below with referenceto the accompanying drawings. The embodiments are illustrative only, andare not intended to limit this disclosure.

FIGS. 4-8 are schematic diagrams of five application scenarios in anembodiment of this disclosure. In such scenarios, a case will occurwhere “at a TTI moment when UE has sufficient uplink grants (UL grants)for transmitting triggered ProSe BSRs, all ProSe Destinations of the UEhave no available to-be-transmitted data”.

As shown in FIG. 4, in this scenario, at a certain TTI (such as TTI-1shown in FIG. 4), a Periodic-ProSeBSR-Timer expires, and at this moment,a periodic ProSe BSR is triggered. However, at this TTI, there exists nodata available for transmission in a sidelink buffer of the UE. At a TTIwhen the UE has sufficient uplink grants for transmitting triggeredProSe BSRs (such as TTI-2 shown in FIG. 4), there still exists no dataavailable for transmission in the sidelink buffer of the UE.

As shown in FIG. 5, in this scenario, at a certain TTI (such as TTI-1shown in FIG. 5), a ProSe BSR is triggered. At this TTI, the UE at leasthas one ProSe destination having data available for transmission. Beforethe ProSe BSR is triggered, the UE has obtained a PDCCH with SL grantsby decoding. At or before a TTI when the UE has sufficient uplink grantsfor transmitting triggered ProSe BSRs (such as TTI-2 shown in FIG. 5),all data available for transmission have been transmitted by using theabove-described SL grants.

As shown in FIG. 6, in this scenario, at a certain TTI (such as TTI-1shown in FIG. 6), a ProSe BSR is triggered. At this TTI, the UE at leasthas one ProSe destination having data available for transmission. Beforethe ProSe BSR is triggered, the UE has obtained a PDCCH with SL grantsby decoding, and the SL grants are used for an SC period containing aTTI at which ProSe BSRs can be transmitted (such as TTI-2 shown in FIG.6). At a TTI when the UE has sufficient uplink grants for transmittingtriggered ProSe BSRs (such as TTI-2 shown in FIG. 6), remaining SLgrants in the above-described SL grants may accommodate all dataavailable for transmission.

As shown in FIG. 7, in this scenario, at a certain TTI (such as TTI-1shown in FIG. 7), a ProSe BSR is triggered. At this TTI, the UE at leasthas one ProSe destination having data available for transmission. Beforethe ProSe BSR is triggered, the UE has obtained a PDCCH with SL grantsby decoding, and the SL grants are used for an SC period next to an SCperiod containing a TTI at which ProSe BSRs can be transmitted. At a TTIwhen the UE has sufficient uplink grants for transmitting triggeredProSe BSRs (such as TTI-2 shown in FIG. 7), remaining SL grants in theabove-described SL grants may accommodate all data available fortransmission.

As shown in FIG. 8, in this scenario, at a certain TTI (such as TTI-1shown in FIG. 8), a ProSe BSR is triggered. At this TTI, the UE at leasthas one ProSe destination having data available for transmission. Beforethe ProSe BSR is triggered, the UE has obtained a PDCCH with SL grantsby decoding, and the SL grants are used for an SC period secondarilynext to an SC period containing a TTI at which ProSe BSRs can betransmitted. At a TTI when the UE has sufficient uplink grants fortransmitting triggered ProSe BSRs (such as TTI-2 shown in FIG. 8),remaining SL grants in the above-described SL grants may accommodate alldata available for transmission.

The above scenarios are examples only, the embodiments of thisdisclosure are applicable to, in addition to the above scenarios, otherimplementable scenarios. The embodiments of this disclosure shall bedescribed below with reference to the accompanying drawings.

Embodiment 1

An embodiment of this disclosure provides a method for processing abuffer status report, applicable to user equipment (UE). FIG. 9 is aflowchart of the method. As shown in FIG. 9, the method includes:

step 901: whether in an TTI where an allocated uplink resource for theTTI is capable of accommodating a ProSe BSR MAC CE containing a bufferstatus for at least one ProSe Destination and its corresponding MACsubheader is judged; if yes, step 902 is executed;

otherwise, the process is terminated;

step 902: whether there exist side-link data available for transmissionin the TTI is judged; and if no, step 903 is executed; otherwise, step904 is executed;

wherein, the judgment here may be performed according to data actuallyexisted in the sidelink buffer; if there actually exist data in thebuffer, it is judged yes, and step 904 is executed; and if thereactually exists no data in the buffer, it is judged no, and step 903 isexecuted;

step 903: all triggered ProSe BSRs are cancelled; and

step 904: contents of the ProSe BSRs, i.e. contents of the ProSe BSR MACCE, are determined according to the side-link data available fortransmission, and then the ProSe BSRs are reported at the TTI.

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is capable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader (it is judged yes in step 901), if there exists noside-link data available for transmission in the TTI (it is judged no instep 902), all the triggered ProSe BSRs are cancelled (step 903); hence,a problem that contents of a ProSe BSR MAC CE to be transmitted areunable to be determined in scenarios 1 and 2 is solved.

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is capable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader (it is judged yes in step 901), if there exist side-linkdata available for transmission in the TTI (it is judged yes in step902), contents of the ProSe BSRs, that is, contents of the ProSe BSR MACCE, may be determined according to the side-link data available fortransmission by using an existing method or other implementable methods,and then the ProSe BSRs are reported at the TTI for reporting ProSe BSRs(step 904).

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is incapable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader (it is judged no in step 901), no ProSe BSR needs to bereported, hence, contents of the ProSe BSR MAC CE need not to bedetermined, that is, the problem in scenarios 1 and 2 does not exist,and no processing is needed.

In an implementation of this embodiment, before step 902, for example,before or after step 901, the method of this embodiment may furtherinclude a step as follows:

step 900 (not shown): after obtaining a PDCCH with an SL grant bydecoding or at a beginning of an SC period for the SL grant, a size ofdata that can be transmitted in the whole SC period to which the SLgrant corresponds is determined according to resources allocated in theSL grant for transmitting data, and all SL MAC PDUs that can betransmitted in the SC period to which the SL grant corresponds aregenerated according to the size of data that can be transmitted.

In this embodiment, as the SL grant obtained by decoding is taken intoaccount, all SL MAC PDUs that can be transmitted in the SC period towhich the SL grant obtained by decoding corresponds are built first, andthen whether there exist side-link data available for transmission atthe TTI for reporting ProSe BSRs is judged. Hence, even though thereexist data to be transmitted, the data shall not be taken into account,as their SL MAC PDUs have been built, and it is judged there exist noside-link data available for transmission. Therefore, not only theproblem that contents of a ProSe BSR MAC CE to be transmitted are unableto be determined in scenarios 1 and 2 is solved, but also a problem thatcontents of a ProSe BSR MAC CE to be transmitted are unable to bedetermined in scenarios 3, 4 and 5 is solved.

In an implementation of this embodiment, after step 902, if there existside-link data available for transmission at the TTI for reporting ProSeBSRs, the method may further include steps as follows:

S1: whether there exists a remaining configured SL grant is judged, S2is executed when it is judged yes, and step 904 is executed when it isjudged no; and

S2: whether all the side-link data available for transmission can beaccommodated by the remaining configured SL grant is judged, step 903 isexecuted when it is judged yes, and step 904 is executed when it isjudged no.

In this implementation, the configured SL grant may be a configured SLgrant for an SC period next to the SC period containing the TTI. If theconfigured SL grant for the SC period next to the SC period containingthe TTI is capable of accommodating all the side-link data available fortransmission, such as in the case described in scenario 4, althoughthere exist side-link data available for transmission in the SC periodnext to the SC period containing the TTI, the side-link data availablefor transmission have an SL grant already, and the SL grant is capableof accommodating all the side-link data available for transmission.Hence, there exists actually no side-link data available fortransmission, and all the triggered ProSe BSRs are cancelled.

In this implementation, the configured SL grant may also be a configuredSL grant for an SC period secondarily next to the SC period containingthe TTI. If the configured SL grant for the SC period secondarily nextto the SC period containing the TTI is capable of accommodating all theside-link data available for transmission, such as in the case describedin scenario 5, although there exist side-link data available fortransmission in the SC period secondarily next to the SC periodcontaining the TTI, the side-link data available for transmission havean SL grant already, and the SL grant is capable of accommodating allthe side-link data available for transmission. Hence, there existsactually no side-link data available for transmission, and all thetriggered ProSe BSRs are cancelled.

In this implementation, if it is judged no in S1 or S2, contents ofProSe BSRs, that is, contents of the ProSe BSR MAC CE, may be determinedaccording to side-link data available for transmission with those thatmay be accommodated by the SL grant being excluded, and then the ProSeBSRs are reported at the TTI.

With the method of this embodiment, a problem that UE is unable todetermine contents of a ProSe BSR MAC CE to be transmitted at a TTI whentriggered ProSe BSRs can be transmitted is solved.

Embodiment 2

An embodiment of this disclosure provides a method for processing abuffer status report, applicable to user equipment (UE). FIG. 10 is aflowchart of the method. As shown in FIG. 10, the method includes:

step 1001: whether in an TTI where an allocated uplink resource for theTTI is capable of accommodating a ProSe BSR MAC CE containing a bufferstatus for at least one ProSe Destination and its corresponding MACsubheader is judged; if yes, step 1002 is executed; otherwise, theprocess is terminated;

step 1002: whether there exist side-link data available for transmissionin the TTI is judged; and if no, step 1003 is executed; otherwise, step1004 is executed;

wherein, the judgment may be performed according to data actuallyexisted in the sidelink buffer, and may also be performed according todata actually existed in the sidelink buffer and an SL grant obtained bydecoding, which shall be described below;

step 1003: all triggered ProSe BSRs are cancelled; and

step 1004: contents of the ProSe BSRs, i.e. contents of the ProSe BSRMAC CE, are determined according to the side-link data available fortransmission, and then the ProSe BSRs are reported at the TTI.

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is capable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader (it is judged yes in step 1001), if there exists noside-link data available for transmission in the TTI (it is judged no instep 1002), all the triggered ProSe BSRs are cancelled (step 1003).

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is capable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader (it is judged yes in step 1001), if there exist side-linkdata available for transmission in the TTI (it is judged yes in step1002), contents of the ProSe BSRs, that is, contents of the ProSe BSRMAC CE, may be determined according to the side-link data available fortransmission by using an existing method or other implementable methods,and then the ProSe BSRs are reported at the TTI for reporting ProSe BSRs(step 1004).

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is incapable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader (it is judged no in step 1001), no ProSe BSR needs to bereported, hence, contents of the ProSe BSR MAC CE need not to bedetermined, and at this moment, no processing is needed.

In an implementation of step 1002, whether there exist side-link dataavailable for transmission can be judged according to whether thereactually exist data in a side-link buffer, that is, if there actuallyexist data in a side-link buffer, a judgment result of step 1002 is yes;otherwise, a judgment result is no.

In this implementation, if the UE obtains the configured SL grant bydecoding a PDCCH, after obtaining the PDCCH with an SL grant by decodingor at a beginning of an SC period for the SL grant, the UE may determinea size of data that can be transmitted in the whole SC period to whichthe SL grant corresponds according to resources allocated in the SLgrant for transmitting data, and may generate all SL MAC PDUs that canbe transmitted in the SC period to which the SL grant correspondsaccording to the size of data that can be transmitted.

Hence, as the SL grant obtained by decoding is taken into account, allSL MAC PDUs that can be transmitted in the SC period to which the SLgrant obtained by decoding corresponds are built first, and then whetherthere exist data available for transmission at the TTI for reportingProSe BSRs is judged.

In this implementation, the configured SL grant may be a configured SLgrant for an SC period next to the SC period containing the TTI and/or aconfigured SL grant for an SC period secondarily next to the SC periodcontaining the TTI.

In another implementation of step 1002, whether there exist side-linkdata available for transmission may be judged according to whether thereactually exist data in a side-link buffer and whether there exists aconfigured SL grant. That is, whether there actually exist data in aside-link buffer is judged. If it is judged no, a judgment result instep 1002 is no; and if it is judged yes, whether there exists remainingSL grant is further judged. If it is judged no, a judgment result instep 1002 is yes; and if it is judged yes, whether the remaining SLgrant is capable of accommodating all side-link data available fortransmission in the sidelink buffer is further judged. If it is judgedyes, a judgment result in step 1002 is no; otherwise, a judgment resultin step 1002 is yes.

In this implementation, if the UE obtains the configured SL grant bydecoding a PDCCH, at each TTI moment to which the SL grants correspond,the UE determines a size of data that can be transmitted in each TTIaccording to resources allocated in the SL grants for transmitting data,and generates SL MAC PDUs that can be transmitted in each TTI accordingto the size of data that can be transmitted.

In this implementation, the configured SL grant may be a configured SLgrant for an SC period next to the SC period containing the TTI and/or aconfigured SL grant for an SC period secondarily next to the SC periodcontaining the TTI.

With the method of this embodiment, a problem that UE is unable todetermine contents of a ProSe BSR MAC CE to be transmitted at a TTI whentriggered ProSe BSRs can be transmitted is solved.

Embodiment 3

An embodiment of this disclosure further provides a method forprocessing a buffer status report, applicable also to user equipment(UE). FIG. 11 is a flowchart of the method. As shown in FIG. 11, themethod includes:

step 1101: whether in an TTI where an allocated uplink resource for theTTI is capable of accommodating a ProSe BSR MAC CE containing a bufferstatus for at least one ProSe Destination and its corresponding MACsubheader is judged; if yes, step 1102 is executed; otherwise, theprocess is terminated;

step 1102: whether there exist side-link data available for transmissionin the TTI is judged; and if there exist no side-link data available fortransmission in the TTI, that is, it is judged no, step 1103 isexecuted; otherwise, step 1104 is executed;

step 1103: a ProSe BSR MAC CE with N being 1 and its corresponding MACsubheader is reported, or a ProSe BSR MAC CE having only one buffer sizedomain and its corresponding MAC subheader is reported, or only one MACsubheader is reported; and

step 1104: contents of the ProSe BSRs, i.e. contents of the ProSe BSRMAC CE, are determined according to the side-link data available fortransmission, and then the ProSe BSRs are reported at the TTI.

In an implementation of step 1102, whether there exist side-link dataavailable for transmission may be judged according to whether thereactually exist data in a side-link buffer, that is, if there actuallyexist data in a side-link buffer, a judgment result of step 1102 is yes;otherwise, a judgment result is no.

In another implementation of step 1102, whether there exist side-linkdata available for transmission may be judged according to whether thereactually exist data in a side-link buffer and whether there exists aconfigured SL grant. That is, whether there actually exist data in aside-link buffer is judged. If it is judged no, a judgment result instep 1102 is no; and if it is judged yes, whether there exists remainingSL grant is further judged. If it is judged no, a judgment result instep 1102 is yes; and if it is judged yes, whether the remaining SLgrant is capable of accommodating all side-link data available fortransmission in the sidelink buffer is further judged. If it is judgedyes, a judgment result in step 1102 is no; otherwise, a judgment resultin step 1102 is yes.

In this embodiment, the configured SL grant may be a configured SL grantfor an SC period next to the SC period containing the TTI and/or aconfigured SL grant for an SC period secondarily next to the SC periodcontaining the TTI.

The method of this embodiment is similar to those of embodiments 1 and2, with the exception that in the methods of embodiments 1 and 2, whenit is judged that there exists no side-link data available fortransmission at the TTI for reporting ProSe BSRs, all the triggeredProSe BSRs are cancelled, while in this embodiment, when it is judgedthat there exists no side-link data available for transmission at theTTI for reporting ProSe BSRs, a ProSe BSR of a special format isreported.

In an implementation, the ProSe BSR of a special format may be a ProSeBSR MAC CE with N being 1 and its corresponding MAC subheader; wherein,N is the number of ProSe destinations contained in the ProSe BSR MAC CE.

FIG. 12 is a schematic diagram of the format of the ProSe BSR MAC CE ofthis implementation. In FIG. 12, “Group index” is an index of a group,“LCG ID” is an ID of a logic channel group, “buffer size” is a size of abuffer, a value of which being 0 in this implementation, and “R” is areserved bit.

In this implementation, a format of the MAC subheader corresponding tothe ProSe BSR MAC CE shown in FIG. 12 is as shown in FIG. 13 or FIG. 14;however, this embodiment is not limited thereto. In the format of theMAC subheader shown in FIG. 13 and FIG. 14, “LCID” may be of anewly-defined value, which is referred to as a predefined value in thisembodiment, and is used to indicate the format and/or a length of theProSe BSR MAC CE to which it corresponds, with its value may be 11000,and 10110, etc., in this implementation. As shown in FIG. 13, “E” is anexpanded bit, which is used to indicate whether it is another MACsubheader or an MAC PDU or an MAC CE after this MAC subheader. As shownin FIG. 14, bit “F” is used to indicate the number of bytes occupied bybit L, L being used to indicate a length of an MAC CE or an MAC PDU towhich this MAC subheader corresponds.

In another implementation, the ProSe BSR of a special format may be aProSe BSR MAC

CE having only one buffer size domain and its corresponding MACsubheader.

FIG. 15 is a schematic diagram of the format of the ProSe BSR MAC CE ofthis implementation. In FIG. 15, “R” is a reserved bit, and “buffersize” is a size of a buffer, a value of which being 0 in thisimplementation. In this implementation, in the ProSe BSR MAC CE, Groupindex and LCG ID are not contained.

In this implementation, a format of the MAC subheader corresponding tothe ProSe BSR MAC CE shown in FIG. 15 is as shown in FIG. 13; however,this embodiment is not limited thereto. In this implementation, the LCIDhas a meaning as described above, and it may be of a newly-definedvalue, which shall not be described herein any further.

In another implementation, the ProSe BSR of a special format may haveonly one MAC subheader, such as the MAC subheader shown in FIG. 13. Inthis implementation, the LCID in the MAC subheader has a meaning asdescribed above, and it may be of a newly-defined value, which shall notbe described herein any further.

In this embodiment, contents identical to those in Embodiment 1 or 2,such as steps 1001, 1002 and 1004, shall not be described herein anyfurther.

In this embodiment, in an TTI, when an allocated uplink resource for theTTI is capable of accommodating a ProSe BSR MAC CE containing a bufferstatus for at least one ProSe Destination and its corresponding MACsubheader, if there exist no side-link data available for transmissionin the TTI, a ProSe BSR MAC CE with N being 1 (FIG. 12) and itscorresponding MAC subheader (FIG. 13 or 14) are reported, or a ProSe BSRMAC CE having only one buffer size domain (FIG. 15) and itscorresponding MAC subheader (FIG. 13) are reported, or only one MACsubheader (FIG. 13) is reported, thereby solving a problem that UE isunable to determine contents of a ProSe BSR MAC CE to be transmitted ata TTI when triggered ProSe BSRs can be transmitted.

Embodiment 4

An embodiment of this disclosure further provides a method forprocessing a buffer status report, applicable also to user equipment(UE). FIG. 16 is a flowchart of the method. As shown in FIG. 16, themethod includes:

step 1601: whether a first triggering condition for a padding ProSe BSRor a periodic ProSe BSR is satisfied is judged, and step 1602 isexecuted if yes, otherwise, step 1604 is executed;

step 1602: whether UE has side-link data available for transmission forany sidelink traffic logic channel is judged, and step 1603 is executedif yes, otherwise, step 1604 is executed;

step 1603: the padding ProSe BSR or the periodic ProSe BSR is triggered;

step 1604: the padding ProSe BSR or the periodic ProSe BSR is nottriggered.

In this embodiment, the first triggering condition may be a triggeringcondition for a padding ProSe BSR or a periodic ProSe BSR defined in anexisting standard, such as a condition defined in document “http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_88/Docs/R2-145307”, and may also beother established triggering conditions.

In this embodiment, when the first triggering condition is satisfied,the padding ProSe BSR or the periodic ProSe BSR is not triggered first,rather, whether UE has side-link data available for transmission for anysidelink traffic logic channel (STCH) is judged; if yes, the paddingProSe BSR or the periodic ProSe BSR is triggered; otherwise, it is nottriggered. Hence, when the UE has no side-link data available fortransmission for any sidelink traffic logic channel, the padding ProSeBSR or the periodic ProSe BSR is not triggered, thereby solving aproblem that UE is unable to determine contents of a ProSe BSR MAC CE tobe transmitted at a TTI when triggered ProSe BSRs can be transmitted.

Embodiment 5

An embodiment of this disclosure further provides a method forprocessing a buffer status report, applicable also to user equipment(UE). FIG. 17 is a flowchart of the method. As shown in FIG. 17, themethod includes:

step 1701: whether a first triggering condition for a ProSe BSR (apadding ProSe BSR or a periodic ProSe BSR or a regular ProSe BSR) issatisfied is judged, step 1702 is executed if yes and the ProSe BSR is apadding ProSe BSR or a periodic ProSe BSR, and step 1703 is executed ifyes and the ProSe BSR is a regular ProSe BSR, otherwise, step 1706 isexecuted;

step 1702: whether UE has side-link data available for transmission forany sidelink traffic logic channel is judged, and step 1703 is executedif yes, otherwise, step 1706 is executed;

step 1703: whether there exists a remaining configured SL grant isjudged, and step 1704 is executed if yes, otherwise, step 1705 isexecuted;

step 1704: whether the remaining configured SL grant is capable ofaccommodating all side-link data available for transmission is judged,and step 1706 is executed if yes, otherwise, step 1705 is executed;

step 1705: the padding ProSe BSR or the periodic ProSe BSR or theregular ProSe BSR is triggered;

step 1706: the padding ProSe BSR or the periodic ProSe BSR or theregular ProSe BSR is not triggered.

In this embodiment, for the padding ProSe BSR, the periodic ProSe BSRand the regular ProSe BSR, the first triggering condition in step 1701may be a triggering condition for a padding ProSe BSR or a periodicProSe BSR or a regular ProSe BSR defined in an existing standard, suchas a condition defined in document“http://www.3gpp.org/ftp/tsg_ran/WG2_RL2/TSGR2_88/Docs/R2-145307”, andmay also be other established triggering conditions.

In this embodiment, when the first triggering condition for the paddingProSe BSR or the periodic ProSe BSR is satisfied, the padding ProSe BSRor the periodic ProSe BSR is not triggered first, rather, whether UE hasside-link data available for transmission for any sidelink traffic logicchannel (STCH) is judged; if no, the UE does not trigger the paddingProSe BSR or the periodic ProSe BSR; and if yes, whether there exists aremaining configured SL grant is further judged. If there exists noremaining configured SL grant, the UE triggers the padding ProSe BSR orthe periodic ProSe BSR. If there exists a remaining configured SL grant,the UE judges whether the configured SL grant is capable ofaccommodating side-link data available for transmission of all sidelinktraffic logic channels. If it is judged no, UE triggers the paddingProSe BSR or the periodic ProSe BSR. And if it is judged yes, the UEdoes not trigger the padding ProSe BSR or the periodic ProSe BSR.

In this embodiment, when the first triggering condition for the regularProSe BSR is satisfied, the regular ProSe BSR is not triggered first,rather, whether there exists a remaining configured SL grant is judged.If no, the UE triggers the regular ProSe BSR. If there exists aremaining configured SL grant, the UE judges whether the SL grant iscapable of accommodating side-link data available for transmission ofall sidelink traffic logic channels. If it is judged no, UE triggers theregular ProSe BSR. And if it is judged yes, the UE does not trigger theregular ProSe BSR.

Hence, when the UE has no side-link data available for transmission forany sidelink traffic logic channel, the UE does not trigger the paddingProSe BSR or the periodic ProSe BSR; and when the UE has side-link dataavailable for transmission but the remaining configured SL grant iscapable of accommodating all these data, the UE does not trigger thepadding ProSe BSR or the periodic ProSe BSR or the regular ProSe BSR,thereby solving a problem that UE is unable to determine contents of aProSe BSR MAC CE to be transmitted at a TTI when triggered ProSe BSRscan be transmitted.

In this embodiment, the configured SL grant may be a configured SL grantfor an SC period next to the SC period containing the TTI and/or aconfigured SL grant for an SC period secondarily next to the SC periodcontaining the TTI.

The methods of the embodiments are described above in five embodiments.And in particular implementation, the five embodiments may be combined,or may be used separately. For example, embodiments 1 and 2 may becombined with embodiments 4 and 5, embodiment 3 may be combined withembodiments 4 and 5, and embodiments 1, 2, 3, 4 and 5 may implementedrespectively.

Embodiment 6

The embodiment of this disclosure provides an apparatus for processing abuffer status report, applicable to user equipment. As principles of theapparatus for solving problems are similar to those of the methods ofembodiments 1 and 2, the implementation of the methods of embodiments 1and 2 may be referred to for implementation of the apparatus, withidentical contents being not going to be described herein any further.

FIG. 18 is a schematic diagram of a structure of the apparatus.Referring to FIG. 18, the apparatus 1800 for processing a buffer statusreport includes a first judging unit 181, a second judging unit 182 anda cancelling unit 183.

In this embodiment, the first judging unit 181 is configured to judgewhether in an TTI where an allocated uplink resource for the TTI iscapable of accommodating a ProSe BSR MAC CE containing a buffer statusfor at least one ProSe Destination and its corresponding MAC subheader.

In this embodiment, the second judging unit 182 is configured to, whenit is judged yes by the first judging unit 181, judge whether thereexist side-link data available for transmission in the TTI; wherein, ajudgment manner of the second judging unit 182 is slightly differentfrom those in embodiments 1 and 2, and embodiments 1 and 2 may bereferred to for details.

In this embodiment, the cancelling unit 183 is configured to, when it isjudged no by the second judging unit 182, cancel all triggered ProSeBSRs.

In this embodiment, within a TTI, when the allocated uplink resource forthe TTI is capable of accommodating the ProSe BSR MAC CE containing abuffer status for at least one ProSe Destination and its correspondingMAC subheader, if there exists no side-link data available fortransmission in the TTI, all the triggered ProSe BSRs are cancelled;hence, a problem that UE is unable to determine contents of a ProSe BSRMAC CE to be transmitted at a TTI moment when triggered ProSe BSRs canbe transmitted is solved.

In an implementation, the apparatus 1800 for processing a buffer statusreport further includes a determining unit 184 and a generating unit185.

In this implementation, the determining unit 184 is configured to, afterthe UE decodes and obtains a PDCCH with an SL grant or at a beginning ofan SC period for the SL grant, determine a size of data that can betransmitted in the whole SC period to which the SL grant correspondsaccording to resources allocated in the SL grant for transmitting data.

In this implementation, the generating unit 185 is configured togenerate all SL MAC PDUs that can be transmitted in the SC period towhich the SL grant corresponds according to the size of data that can betransmitted determined by the determining unit 184.

In this implementation, all SL MAC PDUs that can be transmitted in theSC period to which the SL grant corresponds are built first, and thenwhether there exist side-link data available for transmission at the TTIfor transmitting ProSe BSRs is judged. Therefore, not only the problemin scenarios 1 and 2 is solved, but also a problem in scenarios 3, 4 and5 is solved.

In an implementation, the apparatus 1800 for processing a buffer statusreport further includes a third judging unit 186 and a fourth judgingunit 187. In this implementation, the third judging unit 186 isconfigured to, when it is judged that there exist side-link dataavailable for transmission in the TTI for transmitting ProSe BSRs by thesecond judging unit 182, judge whether there exists a remainingconfigured SL grant; and the fourth judging unit 187 is configured to,when it is judged yes by the third judging unit 186, judge whether theremaining configured SL grant is capable of accommodating all theside-link data available for transmission. The cancelling unit 183 isconfigured to cancel all the triggered ProSe BSRs when it is judged yesby the fourth judging unit 187.

In this implementation, the configured SL grant may be a configured SLgrant for an SC period next to the SC period containing the TTI, therebysolving the problem in scenario 3.

In this implementation, the configured SL grant may be a configured SLgrant for an SC period secondarily next to the SC period containing theTTI, thereby solving the problem in scenario 5.

In this embodiment, the second judging unit 182 may judge whether thereexist side-link data available for transmission according to dataactually existed in a side-link buffer. If there actually exist data inthe side-link buffer, the second judging unit judges that there existside-link data available for transmission; otherwise, the second judgingunit judges that there exists no side-link data available fortransmission. Embodiment 2 may be referred to for details, which shallnot be described herein any further.

In this embodiment, the second judging unit 182 may also judge whetherthere exist side-link data available for transmission according to thedata actually existed in the side-link buffer and the configured SLgrant. If there actually exist data in the side-link buffer and theconfigured SL grant is incapable of accommodating all data existed inthe side-link buffer, the second judging unit judges that there existside-link data available for transmission; otherwise, the second judgingunit judges that there exists no side-link data available fortransmission. Embodiment 2 may be referred to for details, which shallnot be described herein any further.

Embodiment 7

The embodiment of this disclosure provides an apparatus for processing abuffer status report, applicable to user equipment. As principles of theapparatus for solving problems are similar to that of the method ofEmbodiment 3, the implementation of the method of Embodiment 3 may bereferred to for implementation of the apparatus, with identical contentsbeing not going to be described herein any further.

FIG. 19 is a schematic diagram of a structure of the apparatus.Referring to FIG. 19, the apparatus 1900 for processing a buffer statusreport includes a first judging unit 191, a second judging unit 192 anda reporting unit 193.

In this embodiment, principles and implementation processes of the firstjudging unit 191 and the second judging unit 192 are identical to thoseof the first judging unit 181 and the second judging unit 182 ofEmbodiment 6, the contents of which being incorporated herein, whichshall not be described herein any further.

In this embodiment, in an TTI, when an allocated uplink resource for theTTI is capable of accommodating a ProSe BSR MAC CE containing a bufferstatus for at least one ProSe Destination and its corresponding MACsubheader (it is judged yes by the first judging unit 191) and thereexist no data available for transmission in the TTI (it is judged no bythe second judging unit 192), the reporting unit 193 reports a ProSe BSRMAC CE with N being 1 and its corresponding MAC subheader, or reports aProSe BSR MAC CE having only one buffer size domain and itscorresponding MAC subheader, or only reports one MAC subheader.

In this embodiment, an LCID in the MAC subheader is a predefined valuefor indicating the ProSe BSR MAC CE to which it corresponds.

In this embodiment, in an TTI, when an allocated uplink resource for theTTI is capable of accommodating a ProSe BSR MAC CE containing a bufferstatus for at least one ProSe Destination and its corresponding MACsubheader, if there exist no data available for transmission in the TTI,a ProSe BSR of a special format is reported, thereby solving a problemthat UE is unable to determine contents of a ProSe BSR MAC CE to betransmitted at a TTI when triggered ProSe BSRs can be transmitted.

In this embodiment, similar to Embodiment 6, the second judging unit 182may judge whether there exist side-link data available for transmissionaccording to data actually existed in a side-link buffer, and may alsojudge whether there exist side-link data available for transmissionaccording to the data actually existed in the side-link buffer and theconfigured SL grant.

Embodiment 8

The embodiment of this disclosure provides an apparatus for processing abuffer status report, applicable to user equipment. As principles of theapparatus for solving problems are similar to those of the methods ofembodiments 4 and 5, the implementation of the methods of embodiments 4and 5 may be referred to for implementation of the apparatus, withidentical contents being not going to be described herein any further.

FIG. 20 is a schematic diagram of a structure of an implementation ofthe apparatus. Referring to FIG. 20, the apparatus 2000 for processing abuffer status report includes a first judging unit 201, a second judgingunit 202 and a processing unit 203.

In this embodiment, the first judging unit 201 is configured to judgewhether a first triggering condition for a padding ProSe BSR or aperiodic ProSe BSR is satisfied.

In this embodiment, the second judging unit 202 is configured to judgewhether UE has side-link data available for transmission for anysidelink traffic logic channel when it is judged yes by the firstjudging unit 201.

In this embodiment, the processing unit 203 is configured to trigger thepadding ProSe BSR or the periodic ProSe BSR when it is judged yes by thesecond judging unit 202. Furthermore, the processing unit 203 is furtherconfigured not to trigger the padding ProSe BSR or the periodic ProSeBSR when it is judged no by the second judging unit 202.

In this embodiment, when UE has no side-link data available fortransmission for any sidelink traffic logic channel, the padding ProSeBSR or the periodic ProSe BSR is not triggered, even if an originaltriggering condition of the padding ProSe BSR or the periodic ProSe BSRis satisfied, thereby solving a problem that UE is unable to determinecontents of a ProSe BSR MAC CE to be transmitted at a TTI when triggeredProSe BSRs can be transmitted.

FIG. 21 is a schematic diagram of a structure of another implementationof the apparatus. Referring to FIG. 21, the apparatus 2100 forprocessing a buffer status report includes a first judging unit 211, asecond judging unit 212, a third judging unit 213, a fourth judging unit214 and a processing unit 215.

The first judging unit 211 is configured to judge whether a firsttriggering condition for a ProSe BSR is satisfied.

The second judging unit 212 is configured to judge whether UE hasside-link data available for transmission for any sidelink traffic logicchannel when it is judged yes by the first judging unit 211 and theProSe BSR is a padding ProSe BSR or a periodic ProSe BSR.

The third judging unit 213 is configured to judge whether there exists aremaining configured SL grant when it is judged yes by the secondjudging unit or it is judged yes by the first judging unit and the ProSeBSR is a regular ProSe BSR.

The fourth judging unit 214 is configured to judge whether the remainingconfigured SL grant is capable of accommodating all side-link dataavailable for transmission when it is judged yes by the third judgingunit 213.

And the processing unit 215 is configured to not trigger the paddingProSe BSR or the periodic ProSe BSR or the regular ProSe BSR when it isjudged no by the first judging unit 211, or it is judged no by thesecond judging unit 212, or it is judged yes by the fourth judging unit214, and trigger the padding ProSe BSR or the periodic ProSe BSR or theregular ProSe BSR when it is judged no by the third judging unit 213 orit is judged no by the fourth judging unit.

With the apparatus of this embodiment, a problem that UE is unable todetermine contents of a ProSe BSR MAC CE to be transmitted at a TTI whentriggered ProSe BSRs can be transmitted is solved.

Embodiment 9

The embodiment of this disclosure further provides UE, including theapparatus for processing a buffer status report as described inembodiments 6-8.

FIG. 22 is a schematic diagram of a structure of the UE of theembodiment of this disclosure. As shown in FIG. 22, the UE 2200 mayinclude a central processing unit 2201 and a memory 2202, the memory2202 being coupled to the central processing unit 2201. It should benoted that this figure is illustrative only, and other types ofstructures may also be used, so as to supplement or replace thisstructure and achieve a telecommunications function or other functions.

In an implementation, the functions of the apparatus for processing abuffer status report may be integrated into the central processing unit2201, and the central processing unit 2201 carries out functions of theapparatus for processing a buffer status report described in embodiments6-8. In this implementation, the functions of the apparatus forprocessing a buffer status report are incorporated herein, and shall notbe described herein any further.

In another implementation, the apparatus for processing a buffer statusreport and the central processing unit 2201 may be configuredseparately. For example, the apparatus for processing a buffer statusreport may be configured as a chip connected to the central processingunit 2201, with its functions being realized under control of thecentral processing unit 2201.

As shown in FIG. 22, the UE 2200 may further include a communicationmodule 2203, an input unit 2204, an audio processing unit 2205, adisplay 2206 and a power supply 2207. It should be noted that the UE2200 does not necessarily include all the parts shown in FIG. 22, andfurthermore, the UE 2200 may include parts not shown in FIG. 22, and theprior art may be referred to.

As shown in FIG. 22, the central processing unit 2201 is sometimesreferred to as a controller or control, and may include a microprocessoror other processor devices and/or logic devices. The central processingunit 2201 receives input and controls operations of every components ofthe UE 2200.

In this embodiment, the memory 2202 may be, for example, one or more ofa buffer memory, a flash memory, a hard drive, a mobile medium, avolatile memory, a nonvolatile memory, or other suitable devices, whichmay store the above planned network information and deployed networkinformation, and may further store a program executing relatedinformation. And the central processing unit 2201 may execute theprogram stored in the memory 2202, so as to realize information storageor processing, etc. Functions of other parts are similar to those of theprior art, which shall not be described herein any further. The parts ofthe UE 2200 may be realized by specific hardware, firmware, software, orany combination thereof, without departing from the scope of the presentdisclosure.

With the UE of this embodiment, a problem that UE is unable to determinecontents of a ProSe BSR MAC CE to be transmitted at a TTI when triggeredProSe BSRs can be transmitted is solved.

Embodiment 10

The embodiment of this disclosure further provides a communicationsystem. FIG. 23 is a schematic diagram of a topology of thecommunication system of this embodiment. As shown in FIG. 23, thecommunication system 2300 includes UE 2301 and an eNB 2302.

In this embodiment, the eNB 2302 is configured to transmit PDCCHs withSL grants and PDCCHs with UL grants to the UE 2301 at an appropriatetime, which may be carried out by an existing eNB, and shall not bedescribed herein any further.

In this embodiment, the UE 2301 is configured to perform communicationbased on a conventional infrastructure with the eNB 2302, and at thesame time, perform D2D communication with other UEs 2301.

In this embodiment, the UE 2301 may use the method for processing abuffer status report described in embodiments 1-5, that is, carrying outthe functions of the apparatus for processing a buffer status reportdescribed in embodiments 6-8. The contents of embodiments 1-8 areincorporated herein, which shall not be described herein any further.

With the communication system of this embodiment, a problem that UE isunable to determine contents of a ProSe BSR MAC CE to be transmitted ata TTI when triggered ProSe BSRs can be transmitted is solved.

An embodiment of the present disclosure provides a computer readableprogram code, which, when executed in an apparatus for processing abuffer status report or UE, will cause a computer unit to carry out themethod for processing a buffer status report described in embodiments1-5 in the apparatus for processing a buffer status report or the UE.

An embodiment of the present disclosure provides a computer readablemedium, including a computer readable program code, which will cause acomputer unit to carry out the method for processing a buffer statusreport described in embodiments 1-5 in an apparatus for processing abuffer status report or UE.

The above apparatuses and methods of the present disclosure may beimplemented by hardware, or by hardware in combination with software.The present disclosure relates to such a computer-readable program thatwhen the program is executed by a logic device, the logic device isenabled to carry out the apparatus or components as described above, orto carry out the methods or steps as described above. The presentdisclosure also relates to a storage medium for storing the aboveprogram, such as a hard disk, a floppy disk, a CD, a DVD, and a flashmemory, etc.

The present disclosure is described above with reference to particularembodiments. However, it should be understood by those skilled in theart that such a description is illustrative only, and not intended tolimit the protection scope of the present disclosure. Various variantsand modifications may be made by those skilled in the art according tothe principle of the present disclosure, and such variants andmodifications fall within the scope of the present disclosure.

What is claimed is:
 1. A user equipment (UE), the UE comprising: acontroller configured to control to trigger a Buffer Status Report (BSR)if an allocated uplink resource for a Transmission Time Interval (TTI)is capable of accommodating a Sidelink Buffer Status Report (BSR) MediumAccess Control (MAC) Control Element (CE) containing a buffer status forat least one Sidelink Destination and its corresponding MAC subheader;and a transmitter configured to transmit the BSR, wherein, thecontroller controls to cancel all triggered Sidelink BSRs if noside-link data available for transmission exists.
 2. The UE according toclaim 1, wherein the controller, after the UE decodes and obtains aPhysical Downlink Control Channel (PDCCH) with a Sidelink (SL) grant orat a beginning of a scheduling control (SC) period for the SL grant,determines a size of data that can be transmitted in the whole SC periodto which the SL grant corresponds according to resources allocated inthe SL grant for transmitting data; and the controller generates all SLMAC Protocol Data Units (PDUs) that can be transmitted in the SC periodto which the SL grant corresponds according to the size of data that canbe transmitted in the whole SC period.
 3. The UE according to claim 1,wherein the controller, when all the side-link data available fortransmission can be accommodated by a remaining configured SL grant,cancel all the triggered Sidelink BSRs.
 4. The UE according to claim 3,wherein the configured SL grant is a configured SL grant for an SCperiod next to the SC period.
 5. The UE according to claim 3, whereinthe configured SL grant is a configured SL grant for an SC periodsecondarily next to the SC period.
 6. The UE according to claim 1,wherein the controller judges whether there exist side-link dataavailable for transmission according to data actually existed in aside-link buffer.
 7. The UE according to claim 6, wherein if thereactually exist data in the side-link buffer, the controller judges thatthere exist side-link data available for transmission or the controllerjudges that there exist no side-link data available for transmission. 8.The UE according to claim 1, wherein the controller judges whether thereexist side-link data available for transmission according to the dataactually existed in a side-link buffer and a configured SL grant.
 9. TheUE according to claim 8, wherein if there actually exist data in theside-link buffer and the configured SL grant is incapable ofaccommodating all data existing in the side-link buffer, the controllerjudges that there exist side-link data available for transmission or thecontroller judges that there exist no side-link data available fortransmission.
 10. The UE according to claim 1, wherein furthercomprising: a receiver configured to receive from a base station a grantfor side link.
 11. The UE according to claim 1, wherein a LogicalChannel ID (LCID) in the MAC subheader is a predefined value forindicating the Sidelink B S R MAC CE to which it corresponds.
 12. Acommunication method comprising: controlling to trigger a Buffer StatusReport (BSR) if an allocated uplink resource for a Transmission TimeInterval (TTI) is capable of accommodating a Sidelink Buffer StatusReport (BSR) Medium Access Control (MAC) Control Element (CE) containinga buffer status for at least one Sidelink Destination and itscorresponding MAC subheader; and transmitting the BSR, wherein,controlling to cancel all triggered Sidelink BSRs if no side-link dataavailable for transmission exists.
 13. The method according to claim 12,wherein a Logical Channel ID (LCD) in the MAC subheader is a predefinedvalue for indicating the Sidelink BSR MAC CE to which it corresponds.14. A communication system comprising: a User equipment (UE) configuredto control to trigger a Buffer Status Report (BSR) if an allocateduplink resource for a Transmission Time Interval (TTI) is capable ofaccommodating a Sidelink Buffer Status Report (BSR) Medium AccessControl (MAC) Control Element (CE) containing a buffer status for atleast one Sidelink Destination and its corresponding MAC subheader andto transmit the BSR; and, a base station configured to receive the BSRwherein, the UE controls to cancel all triggered Sidelink BSRs if noside-link data available for transmission exists.